Julianne Hough Glammed Up on Dancing With the Stars vs. Dressed Down: Which Look Is Better? (PHOTO)

We don't know how she does it, but Julianne Houghcan go from wearing a ballgown to baggy ripped-up jeans and look just as hot.

The former Dancing With the Starspro made an appearance on the competitive dancing show last night to guest judge for the Season 17 stars and pros. During the show, Jules rocked a black gown with a detailed and sexy neckline. Complementing the dress, her hair looked super chic in a braided updo. We know she looked the part, but how were her judging skills? Her brother Derek Hough thought she did great and even told E! News that it "wasn't weird at all" to see his sis at the judge's panel.

Julianne was a natural judge and dressed to impress during the show. After the live show, the dancer-turned-actress kept her funky hairstyle, but put on something more comfortable — denim pants and a black and white striped shirt — for dinner at Ago Restaurant in West Hollywood, California.

Take a look at Julianne's two very different outfits from last night and let us know which you think is a 10 in the comments below!